177 lines
5.6 KiB
C
177 lines
5.6 KiB
C
/*
|
|
* Copyright (c) 1991 Regents of the University of California.
|
|
* All rights reserved.
|
|
*
|
|
* This code is derived from software contributed to Berkeley by
|
|
* The Mach Operating System project at Carnegie-Mellon University.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed by the University of
|
|
* California, Berkeley and its contributors.
|
|
* 4. Neither the name of the University nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*
|
|
* from: @(#)lock.h 7.3 (Berkeley) 4/21/91
|
|
* $Id: lock.h,v 1.4 1993/07/29 21:45:38 jtc Exp $
|
|
*
|
|
*
|
|
* Copyright (c) 1987, 1990 Carnegie-Mellon University.
|
|
* All rights reserved.
|
|
*
|
|
* Authors: Avadis Tevanian, Jr., Michael Wayne Young
|
|
*
|
|
* Permission to use, copy, modify and distribute this software and
|
|
* its documentation is hereby granted, provided that both the copyright
|
|
* notice and this permission notice appear in all copies of the
|
|
* software, derivative works or modified versions, and any portions
|
|
* thereof, and that both notices appear in supporting documentation.
|
|
*
|
|
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
|
|
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
|
|
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
|
|
*
|
|
* Carnegie Mellon requests users of this software to return to
|
|
*
|
|
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
|
|
* School of Computer Science
|
|
* Carnegie Mellon University
|
|
* Pittsburgh PA 15213-3890
|
|
*
|
|
* any improvements or extensions that they make and grant Carnegie the
|
|
* rights to redistribute these changes.
|
|
*/
|
|
|
|
#ifndef _VM_LOCK_H_
|
|
#define _VM_LOCK_H_
|
|
|
|
/*
|
|
* Locking primitives definitions
|
|
*/
|
|
|
|
#define NCPUS 1 /* XXX */
|
|
|
|
/*
|
|
* A simple spin lock.
|
|
*/
|
|
|
|
struct slock {
|
|
int lock_data; /* in general 1 bit is sufficient */
|
|
};
|
|
|
|
typedef struct slock simple_lock_data_t;
|
|
typedef struct slock *simple_lock_t;
|
|
|
|
/*
|
|
* The general lock structure. Provides for multiple readers,
|
|
* upgrading from read to write, and sleeping until the lock
|
|
* can be gained.
|
|
*/
|
|
|
|
struct lock {
|
|
#ifdef vax
|
|
/*
|
|
* Efficient VAX implementation -- see field description below.
|
|
*/
|
|
unsigned int read_count:16,
|
|
want_upgrade:1,
|
|
want_write:1,
|
|
waiting:1,
|
|
can_sleep:1,
|
|
:0;
|
|
|
|
simple_lock_data_t interlock;
|
|
#else /* vax */
|
|
#ifdef ns32000
|
|
/*
|
|
* Efficient ns32000 implementation --
|
|
* see field description below.
|
|
*/
|
|
simple_lock_data_t interlock;
|
|
unsigned int read_count:16,
|
|
want_upgrade:1,
|
|
want_write:1,
|
|
waiting:1,
|
|
can_sleep:1,
|
|
:0;
|
|
|
|
#else /* ns32000 */
|
|
/* Only the "interlock" field is used for hardware exclusion;
|
|
* other fields are modified with normal instructions after
|
|
* acquiring the interlock bit.
|
|
*/
|
|
simple_lock_data_t
|
|
interlock; /* Interlock for remaining fields */
|
|
boolean_t want_write; /* Writer is waiting, or locked for write */
|
|
boolean_t want_upgrade; /* Read-to-write upgrade waiting */
|
|
boolean_t waiting; /* Someone is sleeping on lock */
|
|
boolean_t can_sleep; /* Can attempts to lock go to sleep */
|
|
int read_count; /* Number of accepted readers */
|
|
#endif /* ns32000 */
|
|
#endif /* vax */
|
|
char *thread; /* Thread that has lock, if recursive locking allowed */
|
|
/* (should be thread_t, but but we then have mutually
|
|
recursive definitions) */
|
|
int recursion_depth;/* Depth of recursion */
|
|
};
|
|
|
|
typedef struct lock lock_data_t;
|
|
typedef struct lock *lock_t;
|
|
|
|
#if NCPUS > 1
|
|
void simple_lock_init();
|
|
void simple_lock();
|
|
void simple_unlock();
|
|
boolean_t simple_lock_try();
|
|
#else /* NCPUS > 1 */
|
|
/*
|
|
* No multiprocessor locking is necessary.
|
|
*/
|
|
#define simple_lock_init(l)
|
|
#define simple_lock(l)
|
|
#define simple_unlock(l)
|
|
#define simple_lock_try(l) (1) /* always succeeds */
|
|
#endif /* NCPUS > 1 */
|
|
|
|
/* Sleep locks must work even if no multiprocessing */
|
|
|
|
void lock_init();
|
|
void lock_sleepable();
|
|
void lock_write();
|
|
void lock_read();
|
|
void lock_done();
|
|
boolean_t lock_read_to_write();
|
|
void lock_write_to_read();
|
|
boolean_t lock_try_write();
|
|
boolean_t lock_try_read();
|
|
boolean_t lock_try_read_to_write();
|
|
|
|
#define lock_read_done(l) lock_done(l)
|
|
#define lock_write_done(l) lock_done(l)
|
|
|
|
void lock_set_recursive();
|
|
void lock_clear_recursive();
|
|
|
|
#endif /* !_VM_LOCK_H_ */
|